 /*******************************************************************************
  * Copyright (c) 2000, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.forms;

 /**
  * Classes that implement this interface can be added to the managed form and
  * take part in the form life cycle. The part is initialized with the form and
  * will be asked to accept focus. The part can receive form input and can elect
  * to do something according to it (for example, select an object that matches
  * the input).
  * <p>
  * The form part has two 'out of sync' states in respect to the model(s) that
  * feed the form: <b>dirty</b> and <b>stale</b>. When a part is dirty, it
  * means that the user interacted with it and now its widgets contain state that
  * is newer than the model. In order to sync up with the model, 'commit' needs
  * to be called. In contrast, the model can change 'under' the form (as a result
  * of some actions outside the form), resulting in data in the model being
  * 'newer' than the content presented in the form. A 'stale' form part is
  * brought in sync with the model by calling 'refresh'. The part is responsible
  * for notifying the form when one of these states change in the part. The form
  * reserves the right to handle this notification in the most appropriate way
  * for the situation (for example, if the form is in a page of the multi-page
  * editor, it may do nothing for stale parts if the page is currently not
  * showing).
  * <p>
  * When the form is disposed, each registered part is disposed as well. Parts
  * are responsible for releasing any system resources they created and for
  * removing themselves as listeners from all event providers.
  *
  * @see IManagedForm
  * @since 3.0
  *
  */
 public interface IFormPart {
     /**
      * Initializes the part.
      *
      * @param form
      * the managed form that manages the part
      */
     void initialize(IManagedForm form);

     /**
      * Disposes the part allowing it to release allocated resources.
      */
     void dispose();

     /**
      * Returns true if the part has been modified with respect to the data
      * loaded from the model.
      *
      * @return true if the part has been modified with respect to the data
      * loaded from the model
      */
     boolean isDirty();

     /**
      * If part is displaying information loaded from a model, this method
      * instructs it to commit the new (modified) data back into the model.
      *
      * @param onSave
      * indicates if commit is called during 'save' operation or for
      * some other reason (for example, if form is contained in a
      * wizard or a multi-page editor and the user is about to leave
      * the page).
      */
     void commit(boolean onSave);

     /**
      * Notifies the part that an object has been set as overall form's input.
      * The part can elect to react by revealing or selecting the object, or do
      * nothing if not applicable.
      *
      * @return <code>true</code> if the part has selected and revealed the
      * input object, <code>false</code> otherwise.
      */
     boolean setFormInput(Object input);

     /**
      * Instructs form part to transfer focus to the widget that should has focus
      * in that part. The method can do nothing (if it has no widgets capable of
      * accepting focus).
      */
     void setFocus();

     /**
      * Tests whether the form part is stale and needs refreshing. Parts can
      * receive notification from models that will make their content stale, but
      * may need to delay refreshing to improve performance (for example, there
      * is no need to immediately refresh a part on a form that is current on a
      * hidden page).
      * <p>
      * It is important to differentiate 'stale' and 'dirty' states. Part is
      * 'dirty' if user interacted with its editable widgets and changed the
      * values. In contrast, part is 'stale' when the data it presents in the
      * widgets has been changed in the model without direct user interaction.
      *
      * @return <code>true</code> if the part needs refreshing,
      * <code>false</code> otherwise.
      */
     boolean isStale();

     /**
      * Refreshes the part completely from the information freshly obtained from
      * the model. The method will not be called if the part is not stale.
      * Otherwise, the part is responsible for clearing the 'stale' flag after
      * refreshing itself.
      */
     void refresh();
 }

